ES2893791T3 - Extraction procedure of an odorant extract with an alternative solvent to conventional solvents - Google Patents

Abstract

Process for extracting an extract of volatile odorant compounds, each having a molecular weight of less than 350 g/mol, from an organic raw material containing volatile odorant compounds, comprising the steps according to which: a) brings into contact in at least one bath, at a temperature between 10 and 70 °C, said organic raw material with dimethyl carbonate used as a solvent in said bath to load said dimethyl carbonate solvent with volatile odorant compounds each having a molecular weight of less than 350 g/mol of said organic material and obtaining a liquid organic phase; b) the liquid organic phase of said bath is collected, comprising dimethyl carbonate loaded with volatile odorant compounds each having a molecular weight of less than 350 g/mol; c) in the event that the collected liquid organic phase comprises an aqueous phase immiscible with the dimethyl carbonate resulting from the organic matter, the liquid organic phase is decanted to separate the dimethyl carbonate loaded with volatile odorant compounds from said immiscible aqueous phase and the aqueous phase is removed; d) dimethyl carbonate is partially removed by evaporation and a preconcentrated extract of volatile odorant compounds is recovered; (e) if, after partial removal of dimethyl carbonate by evaporation, the preconcentrated extract of volatile odorant compounds comprises water, the preconcentrated extract is decanted to remove the water; f) an alcohol is added to the dimethyl carbonate to form an azeotrope with the dimethyl carbonate by azeotropic dragging; and g) the preconcentrated extract of volatile odorant compounds is concentrated by evaporation of the azeotropic mixture to obtain the extract of volatile odorant compounds.

Description

DESCRIPTION

Procedure for extracting an odorant extract with a solvent alternative to conventional solvents [0001] The invention relates to a process for extracting an odorant extract from an organic raw material containing odorant compounds by means of a solvent alternative to traditional solvents. The invention also relates to the odorant extracts obtained in this way and their uses.

[0002] In general, it is known that natural extracts for aromas and perfumes are complex substances, also called "Complex Natural Substances", whose organoleptic properties are directly related, in addition to the quality of the raw materials from which they are obtained, with the manufacturing process.

[0003] The amounts of perfumes and scents in plants are small, and the volatile, even thermally brittle, nature of the molecules that constitute these scents and scents is well known.

[0004] For a substance to have odorant properties, it must have moderate molecular weight, low polarity, some water solubility, high vapor pressure and lipophilicity. On the other hand, it need not have particular functional groups or be chemically reactive (Meierhenrich et al., L'actualité chimique, August-September 2005, no. 289 p. 29-40).

[0005] Furthermore, the preparation of such perfume, fragrance or flavor compounds from natural sources is not readily available or reproducible on a regular basis, and can be very expensive.

[0006] These compounds are isolated, for example, by extraction by steam distillation. However, this process denatures some of the odorant components, and the extracts obtained are not exploitable in terms of quality and/or yield.

[0007] In addition to water vapor, widely used in perfumery in the extraction of plants, organic solvents have been required for perfumed or aromatic extracts.

[0008] After the wine, fatty oils and solid fats (tallow) were used with the enflorado. These solid oils, saturated by the emanations of the flowers, could be taken with ethyl alcohol to obtain an ointment concentrate.

[0009] These labor intensive methods have been progressively abandoned in favor of direct extraction with volatile solvents.

[0010] Extraction processes with a volatile solvent of a compound or composition from a plant raw material are also well known. Extraction with volatile solvents involves dissolving the odorous plant material in a solvent which is then evaporated.

[0011] The plants are placed in extractors and are subjected to successive washings with solvents that are thus loaded with odorant molecules, waxes and pigments. After decantation and filtration, the solvent is evaporated to obtain a strongly odorous paste called more particularly concrete for fresh flowers and leaves and resinoid for the material derived from the treatment of dry plants (roots, moss...). The concrete can give rise to a pure essence called absolute after a series of washes with alcohol and enamels.

[0012] This technique of extraction with a volatile solvent was already commonly practiced in the first half of the 20th century with petroleum ether, benzene, and solvents such as hexane, cyclohexane, methylene chloride are currently used classically. , ethyl acetate, isopropanol, acetone, methanol or ethanol.

[0013] However, water-miscible solvents, such as isopropanol, acetone, methanol or ethanol, are not used in conventional extraction in wet products because the water content of the feed causes a loss of aroma that is detrimental to the finish (distillation of concentrated water in the form of steam that partially or completely deodorizes the extract).

[0014] For example, document US7576049 is known, which discloses the use of a volatile ester such as ethyl acetate for the extraction of aromatic compounds from plant material. This document describes in particular very short extraction times, from 15 seconds to about ten minutes, so as not to extract materials that could be incompatible when mixed with other aromatic compounds, such as certain essential oils.

[0015] However, it is well known in the industry that ethyl acetate used as a pure extraction solvent produces products with acid and acetic (vinegar) notes that are detrimental to the fragrance and can damage industrial facilities (corrosion, joints , etc.).

[0016] Thus, the organoleptic characteristics are not optimal, since ethyl acetate tends to partially hydrolyze into acetic acid during the extraction cycle.

[0017] The solvents currently used for the manufacture of concrete are therefore the most apolar, based on hexane or cyclohexane, or on mixtures that contain them in high proportions, sometimes also on dichloromethane.

[0018] However, considering the toxicity of a petroleum solvent such as hexane, it is particularly dangerous for handlers, due to its toxic vapors (it is very volatile) and requires precautions to avoid any contact of the product with the skin during its use. Also, having to use a petroleum solvent like hexane or cyclohexane is contrary to the principles of green chemistry.

[0019] Furthermore, non-polar solvents, such as methylene chloride or benzene, are even more dangerous.

[0020] In addition, the oil cuts, which are hexanes (several isomers), are never perfectly pure, and due to the low yields of most vegetable concretes, the obtained concentrated extracts are more or less contaminated with molecules, trace , with alliaceous/fat notes depending on the purity of the solvent used and the intrinsic strength of the starting plant extract.

[0021] To do this, the composition and smell of the extracts obtained are substantially different from the raw material.

[0022] In general, there is a real demand to replace traditional solvents, and in particular petroleum solvents, with non-toxic solvents having sufficient volatility and good extraction properties in terms of quality and yield.

[0023] Supercritical CO2 extraction can be an interesting alternative to the use of hexane. However, it is very complex to apply in practice since it requires special equipment, resistant to strong pressures. The investment costs are high for the products obtained. It gives excellent results in terms of organoleptic properties, but the products are generally extracts with a high added value. Thus, supercritical CO2 extraction is not a good alternative to traditional solvents in existing standard industrial equipment.

[0024] EP0616821 is also known which discloses the use of non-chlorinated fluorocarbon solvents.

[0025] More specifically, document WO02/36232 is known which discloses the use of an extraction solvent comprising heptafluoropropane.

[0026] These two documents describe in particular the advantage of using such solvents compared to conventional solvents such as hexane, as they have lower boiling points. According to these documents, the evaporation of the solvent at a temperature above 60 °C leads to the heating of the extract to temperatures that cause a loss of volatile odorant molecules and the denaturation of the extracts.

[0027] However, these compounds are harmful to the ozone layer, since they are especially volatile. Furthermore, as organofluorinated compounds, they should be avoided as solvents.

[0028] Lastly, document US5942597 is known, which discloses a process for extracting polyhydroxyalkanoates and an oil (which must be removed) from raw materials such as plants, and mentions dimethyl carbonate among a long list of solvents for polyhydroxyalkanoates.

[0029] However, the solvent according to the invention is not mentioned in the list as a solvent for the oil to be removed. In addition, the polyhydroxyalkanoates, like the oil commonly composed of triglycerides, extracted by this process are non-odorous, non-volatile compounds with a high molecular weight, greater than 500 g/mol, and cannot be considered as volatile odorant compounds.

[0030] Document CN102002430 is also known, which discloses a process for extracting vegetable oils with dimethyl carbonate.

[0031] The proposals for substitute solvents usually refer to non-volatile green solvents, such as fatty substances, triglycerides or esters, glycerol carbonate, monoterpenes (limonene, pinenes) that have too high boiling points, or even molecules that are considered too polar (ethanol, butanol, isoamyl alcohol, fusel).

[0032] In view of the above, a problem that the invention proposes to solve is to implement a process for extracting an odorant extract from an organic raw material using an alternative non-toxic solvent and not derived from petrochemicals, and that can be implemented in traditional extraction installations. This process is simple to apply, has at least the same and generally much improved performance, and the odorant extracts obtained in this way have a scent that is faithful to that of the raw material, and can be used as a perfume, a perfumery ingredient, a food flavoring or even in the composition of a cosmetic product.

[0033] The method according to the invention offers in particular the following advantages with respect to the prior art:

- the process uses a non-toxic and potentially non-petrochemical solvent;

- the process uses a solvent that has sufficient volatility;

- the process uses a solvent that has a moderate polarity;

- the process uses a solvent that has a good affinity for the desired molecules of organoleptic interest;

- the process uses a solvent that is in the liquid phase at atmospheric pressure under conventional extraction conditions and is therefore suitable for use in conventional extraction plants; - the process uses a solvent that has a much higher solvent power than hexane for the volatile molecules of interest (aromas, fragrances) and, therefore, extraction temperatures and times can be limited. This supposes an economic and ecological advantage;

- the process provides improved yields compared to those obtained for concretes and absolutes by traditional processes, while remaining sufficiently selective for the volatile odorant molecules of interest;

- the odorant extracts obtained have an odor similar to that of the plant, and can be used in perfumery, cosmetics and in the agri-food industry.

[0034] The first object of the invention is, therefore, a process for extracting an extract of volatile odorant compounds from an organic raw material containing odorant compounds comprising the steps according to which: a) it is put into contact in at least one bath, at a temperature between 10 and 70°C, said organic raw material with dimethyl carbonate used as solvent in said bath to load said dimethyl carbonate solvent with volatile odorant compounds of said organic material and obtain a liquid organic phase; b) the liquid organic phase of said bath is collected; c) in the event that the collected liquid organic phase comprises an aqueous phase immiscible with the dimethyl carbonate resulting from the organic matter, the liquid organic phase is decanted to separate the dimethyl carbonate loaded with volatile odorant compounds from said immiscible aqueous phase and the aqueous phase is removed; d) dimethyl carbonate is partially removed by evaporation and a pre-concentrated extract of volatile odorant compounds is recovered; e) if, after partial removal of dimethyl carbonate by evaporation, the preconcentrated extract of volatile odorant compounds comprises water, the preconcentrated extract is decanted to remove the water; and f) concentrating the preconcentrated extract of volatile odorant compounds by evaporation to obtain the extract of volatile odorant compounds.

[0035] The invention and its advantages will be better understood from a reading of the following description and non-limiting embodiments.

[0036] The extraction process according to the invention is used to obtain an odorant extract from an organic raw material containing odorant compounds. The odorant extract according to the invention is more particularly an extract of volatile odorant compounds, preferably an extract of volatile odorant compounds having a molecular weight of less than 350 g/mol.

[0037] Advantageously, the volatile odorant compounds extracted according to the invention have, in addition to a low molecular weight, less than 350 g/mol, an equally low polarity, a certain solubility in water, a high vapor pressure and a high lipophilic character. . In addition, the presence of certain functional groups gives the molecules a specific characteristic odour.

[0038] An extract of volatile odorant compounds according to the invention is an extract that exhales an odour.

[0039] Odor according to the invention means any volatile chemical compound of low molecular weight, preferably less than 350 g/mol, which has organoleptic properties perceptible by olfactory cells and/or the taste organ in sufficient concentration, even at a concentration very low.

[0040] As a non-limiting example of an odor, we can mention any indifferent odor or even a bad odour, and more particularly odoriferous odors that characterize a good odor such as a perfume, an aroma, a flavor or a fragrance that characterize successive odours, olfactory layers.

[0041] By organic raw material containing odorant compounds is meant any material from which it is possible to obtain an odorant extract by extraction. More specifically, by organic raw material is meant a vegetable raw material or a material such as beeswax. Preferably, a vegetable raw material is used.

[0042] Plants are photosynthetic organisms whose walls are made of cellulose. Among the plants are mainly algae and all kinds of land plants such as mosses, ferns, flowering plants, trees, shrubs or herbs.

[0043] In the process according to the invention, the vegetable raw material used is the entire plant or more particularly certain parts such as the bark, leaves, flowers, stems, roots, fruits, seeds, rhizomes, yolks, as well as exudates, gums, seeds, waxes and derivatives.

[0044] According to the invention, moist or freshly picked or dried, ground or ground, preferably semi-moist or dry plant material (sprouts, seeds, pods) is used.

[0045] Non-limiting examples of organic raw materials containing odorant compounds according to the invention are blackcurrant buds, mimosa, vanilla, mate, frankincense, tuberose, vetiver, jasmine, rose, myrrh , iris, benzoin, cocoa, coffee, cistus, labdanum, fenugreek, hay, sandalwood, juniper, ginger, lavender, lavandin, moss, nutmeg, ylang ylang, patchouli, pepper, saffron, tobacco, tea, tonka, geranium, cardamom and beeswax.

[0046] In a first stage of the process according to the invention, the organic raw material is contacted in at least one bath, at a temperature between 10 and 70°C, with the dimethyl carbonate used as solvent to load the solvent of dimethyl carbonate with volatile odorant compounds resulting from the organic matter and obtain a liquid organic phase.

[0047] Dimethyl carbonate is not very dangerous and is not considered toxic, in particular with respect to petroleum solvents such as benzene, hexane or cyclohexane.

[0048] Furthermore, dimethyl carbonate can be obtained from non-petroleum sources. Dimethyl carbonate is a non-toxic and benign substance for the environment. It acts as a solvent minimizing the risk of toxicity.

[0049] Dimethyl carbonate has a moderate polarity close to that of benzene, and is less nonpolar than hexane. Advantageously, dimethyl carbonate does not extract sugars and other highly polar molecules, and has excellent affinity for the desired volatile odorant molecules.

[0050] During the contact according to the invention, the organic raw material is placed, for example, in an extractor comprising dimethyl carbonate used as solvent, liquid at atmospheric pressure, to bathe in the solvent at a moderate temperature between 10 and 70°C, a temperature that depends on the load to be treated and varies according to the nature of the plant to be extracted.

[0051] Advantageously, a moderate heating treatment is carried out with respect to room temperature conditions, preferably at a temperature between 35 and 45°C.

[0052] The duration of the extraction bath according to the invention can be up to several hours, for example from 15 minutes to 10 hours and will influence the olfactory profile of the extracted odorant extract.

[0053] Advantageously, the duration and temperature of the extraction bath according to the invention are optimized depending on the nature of the load, the duration being preferably between approximately 1 hour and approximately 4 hours, which is the necessary and sufficient time to extract the volatile odorant compounds collected in the liquid organic phase and more particularly the dimethyl carbonate loaded with volatile odorant compounds.

[0054] During the bath, the organic raw material can be worked statically, dynamically or under stirring, or in circulation of solvents, for a certain time, for example, gently stirring. Agitation thus provides a less saturated solvent which, in turn, participates in the extraction.

[0055] Advantageously, the bath is carried out in a closed solvent circulation circuit, that is, the solvent it circulates over the organic raw material in such a way as to create a movement in the extractor, without breaking the petals, for example, or shaking the crushed seeds, and to avoid zones of solvent saturation at the periphery of the plant.

[0056] Alternatively, the baths can be carried out in several extractors simultaneously or successively, depending on the amount of organic raw material to be treated.

[0057] For example, a single bath can be carried out followed by a rinse with fresh extraction dimethyl carbonate, several baths with the same organic raw material, possibly several passes of the load in the same volume of solvent, depending on the saturation of the solvent for a raw material/solvent weight ratio of from 1:1 to 1:10, preferably from 1:3 to 1:5.

[0058] The liquid organic phase is then collected from the bath. To do this, the liquid organic phase is separated from the solid organic raw material, if any, in order to collect the liquid organic phase and, more specifically, the dimethyl carbonate loaded with volatile odorant compounds, generally by extracting the miscella, as standard extraction equipment allows.

[0059] Next, in the event that the collected liquid organic phase comprises an aqueous phase immiscible with the dimethyl carbonate resulting from the organic raw material, the liquid organic phase is decanted to separate the dimethyl carbonate loaded with volatile odorant compounds of the immiscible aqueous phase resulting from the organic raw material and the aqueous phase is eliminated.

[0060] Advantageously, dimethyl carbonate is heavier than water with a density of 1060 g/cm3 at 20°C and is poorly soluble in water with a partial solubility of 139 g/L. Thus, by decanting the liquid organic phase of the bath, the dimethyl carbonate loaded with volatile odorant compounds clearly separates from the immiscible aqueous phase resulting from the organic raw material. Therefore, it is very easy to collect the solvent laden with volatile odorant compounds and remove the aqueous phase after decanting the bath.

[0061] According to an embodiment of the extraction process according to the invention, taking into account the density of the dimethyl carbonate, the water is decanted from above, and the solvent laden with volatile odorant compounds is below the aqueous phase to be removed.

[0062] In terms of handling, the fact that the water covers the solvent makes it possible to limit the possible emanations towards the handlers. Thus, handlers who come into contact with the volatile solvent can use water to form a protective layer on the surface and then remove it.

[0063] Only the fraction corresponding to the dimethyl carbonate solvent laden with volatile odorant compounds is then recovered and the aqueous fraction is eliminated.

[0064] Indeed, when a moist or fresh plant is used as organic raw material, unlike a dry or semi-moist plant, which comprises at least 70% water by weight of its total weight, typically around 85% of water, before or after loss on drying due to harvest, for example, a resulting aqueous phase is obtained. This aqueous phase tends to carry unwanted sugars into the odorant extract according to the invention. The sugars are not extracted with pure dimethyl carbonate, but with wet dimethyl carbonate, which is the case with a very humid (fresh flowers) or wet (rain) load. An additional volume-limited aqueous wash may be considered if necessary to remove polar molecules not intended according to the invention, such as a concentrated perfume extract.

[0065] Advantageously, to eliminate the little water that may have been retained in the dimethyl carbonate solvent loaded with volatile odorant compounds, a dehydrating agent such as sodium sulfate or sodium chloride is used. It consists of a drying operation. It is then filtered to collect only the dimethyl carbonate loaded with volatile odorant compounds, without water and, advantageously, without sugars.

[0066] The dimethyl carbonate is then partially removed by evaporation and a preconcentrated odorant extract consisting of volatile odorant compounds is recovered.

[0067] In the event that, after partial removal of the dimethyl carbonate by evaporation, the odorant preconcentrated extract still contains water, the preconcentrated extract is decanted to remove the water.

[0068] Indeed, dimethyl carbonate naturally contains 3% residual water, and is thus pre-concentrated to remove the last traces of water by further decanting.

[0069] Lastly, the odorant pre-concentrated extract is concentrated and, more specifically, the carbonate of dimethyl loaded with volatile odorant compounds by evaporation to obtain the odorant extract formed by volatile odorant compounds, "concrete" or "resinoid".

[0070] Advantageously, the extraction process according to the invention makes it possible to obtain an extract comprising at least 3% of volatile odorant compounds by weight of the total weight of the extract, even more advantageously at least 10%.

[0071] In the event that a particularly dry organic raw material is used and contains little or no water, advantageously no stage is carried out, not even a single stage of decantation and elimination of water. In addition, advantageously, no stage of partial elimination of dimethyl carbonate by evaporation is carried out to obtain an odorant preconcentrated extract; the organic phase collected from the bath is concentrated solely and directly by evaporation to obtain the odorant extract according to the invention.

[0072] Dimethyl carbonate has sufficient volatility for good solvent removal without denaturing the volatile odorant compounds of interest and the odorant extract. It has a boiling point of 90 °C at atmospheric pressure (Pa).

[0073] Thus, the dimethyl carbonate is at least partially eliminated and/or the odorant preconcentrated extract is concentrated by evaporation at a temperature less than or equal to 90 °C.

[0074] Advantageously, evaporation is carried out under vacuum or under partial vacuum, which makes it possible to substantially reduce the evaporation temperature.

[0075] Preferably, the dimethyl carbonate is at least partially evaporated under vacuum at a temperature below 70°C, even more preferably at a temperature below 60°C or even 50°C or even 45°C.

[0076] Even more advantageously, the process according to the invention further comprises a step according to which an alcohol is added to the dimethyl carbonate which forms an azeotrope with the dimethyl carbonate, before removing the dimethyl carbonate and/or concentrate the odorant pre-concentrated extract by azeotropic drag evaporation, while limiting aromatic losses.

[0077] Preferably, a natural and non-toxic compound that forms an azeotropic mixture with the dimethyl carbonate, such as ethanol, is added.

[0078] Dimethyl carbonate advantageously forms azeotropic mixtures with water and with ethanol. These mixtures have boiling temperatures of 78.4 °C and 75.3 °C respectively at atmospheric pressure. Thus, the boiling temperature is substantially reduced to remove the solvent by evaporation in order to obtain the odorant extract according to the invention without denaturing the volatile odorant compounds of interest.

[0079] By way of example, according to a preferred embodiment of the extraction process according to the invention, before complete finishing, an amount of ethanol between 1% and 100% can be added to the concentrated load (ethanol preferably to methanol which is toxic but could be used to advantage on a technical level with its azeotrope at 63.7 °C on dimethyl carbonate loaded with volatile odorant compounds).

[0080] Preferably, azeotropic mixtures are evaporated by concentration in vacuo or partial vacuum. The formation of said azeotropic mixture, combined with an atmosphere under vacuum or under partial vacuum, allows the dimethyl carbonate evaporation temperature to be reduced to a moderate temperature, less than or equal to 60 °C, of the order of 55, 50, 45 or even 40°C.

[0081] Thus, the temperature and duration of heating are advantageously reduced to evaporate the dimethyl carbonate solvent and obtain the odorant extract according to the invention.

[0082] According to the process according to the invention, an odorant extract is recovered consisting of volatile odorant compounds, less greasy than the concretes obtained traditionally, whose odor is substantially faithful to the native odor of the organic raw material extracted.

[0083] Said odorant extract according to the invention is an optionally colored product, largely free of sugars, free of water, rich in volatile odorant compounds and with excellent absolute yields. The absolute is the fraction soluble in 96 V/V ethanol. According to the state of the art, it is obtained by taking the concrete (primary extract) with ethanol, glazing, filtering and/or settling, filtering and then concentrating under vacuum or partial vacuum.

[0084] By way of illustration, some examples of organic raw materials containing volatile odorant compounds extracted according to the process according to the invention are mentioned below: Black currant sprouts:

[0085] 5 kg of blackcurrant sprouts ( Ribes nigrum) were harvested in Burgundy in January 2011, and then shipped and harvested 48 hours after harvest. These shoots were placed in a basket extractor and then immersed in a dimethyl carbonate bath at 35 °C for 2 hours, with the shoots/dimethyl carbonate ratio being 1:3 by weight. The miscella (water extract solvent) or liquid organic phase is extracted. The shoots are extracted twice with the same amount of solvent, shortening the last bath to one hour. The miscella is decanted for 5 minutes to separate the dimethyl carbonate laden with volatile odorant compounds from the immiscible aqueous phase resulting from the blackcurrant sprouts. Dimethyl carbonate loaded with volatile odorant compounds is found below the aqueous phase. The dimethyl carbonate loaded with volatile odorant compounds is recovered by decantation. The volatile odorant-laden dimethyl carbonate is then filtered off without water. It is then concentrated under partial vacuum at 60 °C. Half a volume of ethanol is added to the preconcentrated product and the azeotropic mixture is heated to a temperature of 45 °C so that the dimethyl carbonate and the ethanol evaporate completely. Finally, the odorant extract thus obtained according to the invention is recovered.

[0086] The yield obtained is 7% by mass for the three baths. The extract obtained is a dark green-brown pasty mass with a fruity odor characteristic of fresh blackcurrant shoots.

[0087] Likewise, the following table 1 shows, by means of gas chromatography (GC) in an apolar column, the composition, at least partial, of the volatile odorant compounds (calculated in % with respect to all the volatile compounds of the chromatogram) of the extract of black currant sprouts according to the example.

Tl 1:

Vanilla pods:

[0088] 5 kg of ground vanilla pods ( Vanilla planifolia) are placed in a stirred extractor, then immersed in a bath of dimethyl carbonate at 45 °C for 2 hours, the pods / dimethyl carbonate ratio being 1: 5 in weight. The miscella (water extract solvent) is extracted. The pods are extracted twice with the same amount of solvent, shortening the last bath to one hour. The miscella is decanted for 5 minutes to separate the volatile odorant-laden dimethyl carbonate from the immiscible aqueous phase resulting from the vanilla pods. Dimethyl carbonate loaded with volatile odorant compounds is found below the aqueous phase. The dimethyl carbonate loaded with volatile odorant compounds is recovered by decantation. The volatile odorant-laden dimethyl carbonate is then filtered off without water. It is then concentrated under partial vacuum at 55°C. Half a volume of ethanol is added to the preconcentrated product and the azeotropic mixture is heated to a temperature of 45 °C so that the dimethyl carbonate and the ethanol evaporate completely. Finally, the odorant extract thus obtained according to the invention is recovered.

[0089] The yield obtained is 15% by mass for the three baths. The extract obtained is a thick amber-brown liquid with a sweet, woody and mild smell (vanillin), characteristic of vanilla pods.

[0090] Likewise, the following table 2 shows, by means of gas chromatography (GC) in an apolar column, the composition, at least partial, of the volatile odorant compounds (calculated in % with respect to all the volatile compounds of the chromatogram) of the extract vanilla according to the example.

Blooming branches of mimosa:

[0091] 3 kg of fresh flowering branches of mimosa ( Acacia dealbata) were collected in the Tanneron massif in France (Alpes Maritimes) in February 2011 and extracted within 12 hours of collection. These whole branches were placed in a basket extractor, and then immersed in a dimethyl carbonate bath. at 35 °C for 2 hours, the branch/dimethyl carbonate ratio being 1:5 by weight. The miscella (water extract solvent) is extracted. The branches are extracted twice with the same amount of solvent, shortening the last bath to one hour. The miscella is decanted for 5 minutes to separate the dimethyl carbonate loaded with volatile odorant compounds from the immiscible aqueous phase resulting from the mimosa branches. Dimethyl carbonate loaded with volatile odorant compounds is found below the aqueous phase. The dimethyl carbonate loaded with volatile odorant compounds is recovered by decantation. The volatile odorant-laden dimethyl carbonate is then filtered off without water. It is then concentrated under partial vacuum at 45°C. Half a volume of ethanol is added to the preconcentrated product and the azeotropic mixture is heated to a temperature of 40°C so that the dimethyl carbonate and the ethanol evaporate completely. Finally, the odorant extract thus obtained according to the invention is recovered.

[0092] The yield of the extract is 1.25% on the fresh plant.

[0093] The extract obtained is a dark green paste with a sweet aniseed smell characteristic of fresh mimosa flowers. The absence of greasy notes present in hexanic concrete is noted.

[0094] Likewise, Table 3 shows, by gas chromatography (GC) in an apolar column, the composition, at least partially, of the volatile odorant compounds (calculated in % with respect to all the volatile compounds of the chromatogram) of the extract of mimosa according to the example.

Frankincense gum:

[0095] 5 kg of crushed frankincense ( Boswellia sp.) tears (exudate) are placed in a stirred extractor, and then immersed in a dimethyl carbonate bath at 45 °C for 2 hours, the ratio being tears/ dimethyl carbonate 1:3 by weight. The miscella (extract solvent) or liquid organic phase is extracted. Tears are extracted three times with the same amount of solvent, shortening the last bath to one hour. The dust-free, volatile odorant-laden dimethyl carbonate is recovered by filtration. It is then concentrated under partial vacuum at 55°C. Finally, the odorant extract thus obtained according to the invention is recovered.

[0096] The yield obtained is 67% by mass for the four baths. The product obtained is a very viscous liquid, transparent, amber in color and with a woody and resinous smell characteristic of incense tears.

[0097] Likewise, the following table 4 shows, by gas chromatography (GC) in an apolar column, the composition, at least partial, of the volatile odorant compounds (calculated in % with respect to all the volatile compounds of the chromatogram) of the extract of incense gum according to the example.

Tl 4:

Matte Sheets:

[0098] 3 kg of fragmented mate leaves ( Ilex paraguariensis, Paraguay) are placed in a stirred extractor, and then immersed in a dimethyl carbonate bath at 45 °C for 2 hours, with the proportion of fragments / carbonate being dimethyl 1:5 by weight. The miscella is extracted (extract solvent). The batch is extracted twice with the same amount of solvent, shortening the last bath to one hour. The dust-free, volatile odorant-laden dimethyl carbonate is recovered by filtration. It is then concentrated under partial vacuum at 50°C. Finally, the odorant extract thus obtained according to the invention is recovered.

[0099] The yield obtained is 9% by weight for all baths. The extract is a greenish-gray paste with a characteristic odor of mate leaves, approaching that of green tea or hay.

[0100] Likewise, the following table 5 shows, by gas chromatography (GC) in an apolar column, the composition, at least partial, of the odorant volatile compounds (calculated in % with respect to all the volatile compounds of the chromatogram) of the extract matte according to the example.

May Rose:

[0101] 2 kg of fresh roses ( Rosa centifolia, France) are placed in an extractor, then immersed in a bath of dimethyl carbonate at 25 °C for 2 hours, the flower / dimethyl carbonate ratio being 1:3 in weigh. The miscella is extracted (extract solvent). The batch is extracted twice with the same amount of solvent. Dimethyl carbonate washings loaded with volatile odorant compounds and free of plant debris are recovered by filtration and drying in a drying salt such as sodium sulfate. The concentration is carried out under a vacuum of 150 to 200 mbar, at a temperature of 50 °C, with the addition of ethanol at the end of the concentration. Finally, the odorant extract thus obtained according to the invention is recovered.

[0102] The yield obtained is 0.63% by weight for all baths. This extract is a dark red pasty mass with the scent of rose petals. It can be decanted in the traditional way with ethanol (washing, glazing, filtration, concentration) to obtain a rose absolute. The yield of the absolute in the extract is 79% and in the flowers it is 0.5% (compared to 0.3% in the traditional way).

[0103] Likewise, the following table 6 shows by gas chromatography (GC) in an apolar column the composition, at least partial, of the volatile odorant compounds (calculated in % with respect to the total volatile compounds of the chromatogram) of the rose extract according to the example.

Tl:

Green cardamom:

[0104] 1.5 kg of crushed cardamom seeds ( Ellettaria cardamomum) are placed in a stirred extractor, and then immersed in a bath of dimethyl carbonate at 45°C for 2 hours, being the ratio between cardamom seeds / dimethyl carbonate 1:6 by weight. The miscella (extract solvent) or liquid organic phase is extracted. The batch is extracted twice, the first time with 6 kg and then with 3 kg of dimethyl carbonate, for one hour for each bath. The dimethyl carbonate loaded with volatile odorant compounds is recovered by filtration. It is then dried and concentrated under vacuum at 150 to 200 mbar, at a temperature of 50 °C. Finally, the odorant extract thus obtained according to the invention is recovered.

[0105] The yield obtained is 7% by weight for all baths.

[0106] In addition, the following table 7 shows by gas chromatography (GC) in apolar and polar columns the at least partial composition of the odorant volatile compounds (calculated in % with respect to the total volatile compounds of the chromatogram) of the cardamom extract green according to the example.

[0107] In addition, the following table 8 shows the content of volatile odorant compounds, with a molecular weight of less than 350 g/mol, of the odorant extracts extracted according to the invention from the plant raw materials described in the previous examples. These concentrations of volatile odorant compounds are given by weight of the total weight of the extract.

[0108] Likewise, in the following table 9 the yields of the odorant extracts extracted according to the invention of the different vegetable raw materials described in the previous examples are compared with those of a traditional concrete obtained by extraction with hexane.

Tl:

[0109] Thus, as illustrated above, the process according to the invention has higher yields than those obtained with the traditional hexane extraction process from these same plant raw materials.

[0110] The process according to the invention thus makes it possible to obtain an odorant extract extracted from an organic raw material, preferably a vegetable, by means of dimethyl carbonate not derived from petrochemicals, and which respects the principles of green chemistry and which does not have the same impact on human health, in particular it is not carcinogenic, mutagenic or toxic for reproduction.

[0111] Said fragrant extracts, as exemplified above, are very difficult to characterize as such because they vary, for the same species, depending on different factors such as the raw plant material used, the place of collection or the year of collection, as well as by the equipment used for manufacturing and its settings (vacuum, temperature, duration).

[0112] The extract obtained advantageously comprises at least 3% of volatile odorant compounds by weight of the total weight of the extract, even more advantageously at least 10%.

[0113] The perfuming extract obtained can advantageously be transformed into an absolute according to the procedures of the state of the art with much higher yields than conventional concretes obtained by petroleum solvents of the hexane type, dimethyl carbonate being more polar. The mass balance of the plant to the absolute is particularly advantageous.

[0114] The extract obtained according to the invention by extraction with dimethyl carbonate, or the absolute obtained at From it, it can also be advantageously fractionated by molecular distillation to obtain a clearer extract that is more concentrated in scented molecules.

[0115] The odorant extract obtained can also be used as a food flavoring or in the composition of a cosmetic product.

[0116] As an example of a cosmetic composition, mention may be made of compositions intended for topical application, in particular to the skin, such as a gel, a cream, a milk, a lotion, an oil, a shampoo or a soap.

Claims (8)

1. Process for extracting an extract of volatile odorant compounds, each having a molecular weight of less than 350 g/mol, from an organic raw material containing volatile odorant compounds, comprising the steps according to which: a) in at least one bath, at a temperature between 10 and 70 °C, said organic raw material is contacted with dimethyl carbonate used as a solvent in said bath to load said dimethyl carbonate solvent with volatile odorant compounds that each have a molecular weight of less than 350 g/mol of said organic matter and obtain a liquid organic phase; b) the liquid organic phase of said bath is collected, comprising the dimethyl carbonate loaded with volatile odorant compounds each having a molecular weight of less than 350 g/mol; c) in the event that the collected liquid organic phase comprises an aqueous phase immiscible with the dimethyl carbonate resulting from the organic matter, the liquid organic phase is decanted to separate the dimethyl carbonate loaded with volatile odorant compounds from said immiscible aqueous phase and the aqueous phase is removed; d) dimethyl carbonate is partially removed by evaporation and a preconcentrated extract of volatile odorant compounds is recovered; (e) if, after partial removal of dimethyl carbonate by evaporation, the preconcentrated extract of volatile odorant compounds comprises water, the preconcentrated extract is decanted to remove the water; f) an alcohol is added to the dimethyl carbonate to form an azeotrope with the dimethyl carbonate by azeotropic dragging; and g) the preconcentrated extract of volatile odorant compounds is concentrated by evaporation of the azeotropic mixture to obtain the extract of volatile odorant compounds. 2. Method according to claim 1, in which the organic raw material containing volatile odorant compounds is a vegetable raw material preferably selected from blackcurrant, mimosa, vanilla, mate, incense, tuberose, vetiver, jasmine, rose, myrrh, iris, benzoin, cocoa, coffee, cistus, labdanum, fenugreek, hay, sandalwood, juniper, ginger, lavender, lavandin, moss, nutmeg, ylang ylang, patchouli, pepper, saffron, tea, tonka, geranium, cardamom or Bee wax. 3. Process according to claim 1 or 2, in which the bath is carried out in solvent circulation, static, dynamic or with agitation, for a final weight/weight ratio of raw material to solvent of 1:1 to 1:10. Process according to one of the preceding claims, in which the organic raw material is contacted with dimethyl carbonate for 15 minutes to about 10 hours. Process according to one of the preceding claims, in which the dimethyl carbonate is eliminated and/or the preconcentrated extract of volatile odorant compounds is concentrated by evaporation at a temperature less than or equal to 90°C. Process according to claim 5, in which the evaporation is carried out under vacuum or partial vacuum. Process according to one of claims 1 to 6, in which ethanol is added to dimethyl carbonate to form an azeotrope. Process according to one of the preceding claims, in which the dimethyl carbonate is eliminated and/or the preconcentrated extract of volatile odorant compounds is concentrated by evaporation at a temperature less than or equal to 60°C.